1. Field of the Invention
The present invention relates to a machine tool with a bore diameter measuring apparatus and a tool position compensating apparatus.
2. Description of the Prior Art
In a conventional machine tool, in order to measure a machined bore of a workpiece mounted on the machine tool, a measuring device, provided with a displaceable feeler and a displacement detector, such as a differential transformer, for detecting a displacement amount of the feeder, is inserted into a tool spindle of the machine tool to be moved into engagement with the machined bore. In order to output the measured signal, the measuring device is also provided with conductors which are connected through a connector to an external control circuit. Accordingly, such measuring device cannot be formed integrally with a boring tool which is rotated for boring operations. As a consequence, in order to measure the machined bore, the measuring device has to be inserted into the tool spindle through the aid of an automatic tool change device, and after measurement of the machined bore, the measuring device is exchanged for the boring tool by means of the automatic tool change device. The radial position of the boring tool is then adjusted based upon the measured value for a finish boring operation. In particular, in case where a workpiece is first trial bored and then finished by the boring tool being adjusted based upon the measured result of the workpiece bore machined at trial, the automatic tool change operation thus has to be performed twice, which is time-consuming. Furthermore, misalignment between the boring tool during trial boring and during finish boring is caused as a result of the automatic tool change operation, which effects the accuracy of the finished bore.